1. Field of the Invention
This invention relates to an alkaline battery, a current collector, an electrode, and a method of manufacturing an electrode.
2. Related Background Art
In the past, due to its reliability and weight-saving, the alkaline secondary battery was often used as a power supply for various pieces of equipment from portable devices to large-sized industrial equipment. In recent years, the use of devices which require high output, such as hybrid cars and power tools, is increasing, and alkaline secondary batteries which can provide a high current electric discharge are coming to be required. When used as an alkaline secondary battery for hybrid cars, high current electric discharge, high output per unit weight (weight-saving), and compactness are desired.
In order to obtain high output from such an alkaline secondary battery, a long, thin electrode is usually used. By making the electrode long and thin, its surface area increases, and the reaction resistance between the anode and the cathode falls, so high output is obtained. In another method, the current collector used in the alkaline secondary battery is given a three-dimensional structure, so the surface area of this current collector increases, the contact area between the active substance and this current collector increases, the current-collecting performance of the active material improves and high output is obtained.
For example, a current collector having a three-dimensional structure is known wherein electroconduction treatment and electrolysis plating treatment are given to a urethane foam sheet, and a foam nickel is then obtained by thermal decomposition of this urethane foam. Alternatively, as described in JP-A 08-329956, a three-dimensional mesh structure is known wherein only the surface of a nonwoven fabric is made conductive by giving a predetermined amount of nickel plating to a nonwoven fabric, manufactured by wet-laying organic fibers, without thermal decomposition/removal of this nonwoven fabric.